PLATANISTA. 455 



mucous membrane is loose, strong-fibred, but very open, some fat cells and oily- 

 particles being mingled with the tissue, while elliptical-shaped great bundles of the 

 striped muscular fibres course in different directions, right up almost to the glandular 

 layer in some instances. 



Farotid Gland. — I introduce in this place a short notice of a glandular 

 structure met with in the neighbourhood of the jaw articulation. It has no imme- 

 diate connection with the Eustachian apparatus, and only claims attention here from 

 its proximity. 



Lying immediately behind the attachment of the stylohyal, and 2-50 inches 

 behind the articulation of the lower jaw, and on the same level, is a somewhat 

 crescentic-shaped gland, 2 inches long and 0-75 of an inch broad, in the dolphin 51 

 inches long. This gland is doubtless the parotid, but I have been unable to detect any 

 duct ; my failure to do so is probably attributable to the condition of the specimen. 



Larynx. — (PL XXVIII, figs. 6 and 7). — The opening to the larynx is a transverse 

 slit, 1'25 inch in breadth when closed, and a longitudinally oblong orifice when open, 

 1-25 inch in length and a little more than 0-75 inch in breadth. The tube of the larynx 

 projects forwards and upwards, generally towards the right side, and is 1-25 inch in 

 length. There is nothing remarkable in its form, which coincides with that of other 

 Cetaceans. The mucous membrane lining the base of the epiglottis and the 

 inferior cornua and body of the arytenoids is covered sparsely, in the first locahty, 

 with small papillary processes, which are numerous over the two latter areas. A 

 short fold of mucous membrane stretches backwards to opposite the posterior border 

 of the body of the thyroid cartilage, having begun near the middle of the epiglottidean 

 cartilage and opposite to the tip of the posterior horns of the arytenoids. On each 

 side of the fold, there is a small orifice which I have been able to trace only a very 

 short way, and it appears to be a" bKnd sac, and I cannot detect any trace of a 

 laryngeal pouch. A number of small closed cavities exist in some specimens, but 

 not in others, and are situated over the body of the thyroid and before the ring of 

 the cricoid and are most deceptive, for they simulate natural cavities to a wonderful 

 degree, but the examination of the larynx in four individuals has satisfied me that 

 they are purely adventitious. 



The thyroid cartilage is remarkable for its great lateral expansion. It con- 

 sists of a body with two wings or lateral bars of cartilage projecting outwards and 

 backwards. The body is lingulate, and projects forwards anterior to the lateral bars, 

 while its posterior border is notched. Prom the hinder tbhd of the lateral margin 

 of the body, the bars of cartilage project outwards for 1'50 inch, nearly at right angles 

 to the body, with a slightly backward inchnation, and each wing projects outwards 

 and dorsally to protect the anterior two-thirds of the cricoid. It then bends back- 

 wards and inwards to reach the cricoid. It presents no trace of an anterior horn. 

 The thickness of the posterior portion of the cartilage does not exceed 0"10 inch, but 

 it increases as it approaches the cricoid to more than double that thickness, and the 

 anterior portion of the body is convex superiorly, and thicker than its posterior half, 

 or than the lateral bars. The breadth of the latter structures is about 0'40 inch, but 



